I am currently testing several LTE-M Beacons in a large (approximately 10 hectares) warehouse environment and suspect that in some areas of the warehouse, the LTE-M Beacons are unable to establish an LTE-M connection - I was wondering, is there an undocumented API to get / set the transmit and receive power of the LTE-M modem? Or if not, and indeed it is possible in the hardware configure the LTE-M modem to transmit at a higher power level (at the expense of battery life) could such an API be added? Our use case calls for only occasional transmissions during exceptional situations, so trading off battery life for transmit power makes sense for us. (We are also implementing the functionality of detecting poor connectivity and queueing exceptional events for later transmission when connectivity is good)
There is no undocumented API for setting modem transmit power, because it is not possible to set LTE transmit power in the modem. (Anyway writing about not documented API on public forum would make it some how documented and this defeats purpose of having undocumented API).
LTE network adjusts its TX power automatically depending on received signal strength from base station. It is important because it allows to reduce signal interference with neighbouring cells. Mobile terminals that have ability to increase transmit power above maximum limit specified or in any way ignore power adjusting protocols would not be beneficial for cellular network. Such devices may be considered not compliant and blocked from network and might not be able to get certification.
OK - Thanks for the explanation! In further testing at our location, we are finding that certain devices can successfully achieve an LTE-M connection in the same locations where other devices are not able to achieve an LTE-M connection - we will continue to investigate - it is likely there are several ‘variables’ simultaneously involved, however having a deeper understanding of how LTE works helps.